Solar return — the Sun back at its natal longitude

The calculation needs the natal date, the latitude and longitude used for the return chart, and a year. The return moment is when the Sun’s longitude matches the natal Sun, to the precision of the ephemeris. That moment is rarely exactly midnight on the birthday, and the clock time shifts slightly from year to year.

Casting the chart for that instant, at the place you choose, produces a new set of houses. The Sun’s sign in a solar return is the natal sun sign by construction. The rising sign is not. People who treat “solar return” as another name for the birthday horoscope are skipping the return time.

The public website does not generate a solar-return page per sign, because every Aries Sun shares a sign and does not share a return clock time. The birth chart remains the public tool. The return is a second chart built from the natal Sun’s degree.

If the natal Sun is at 15.42° Aries, the return is the UTC instant the transiting Sun is again at 15.42°, not the calendar morning of the birthday and not 0° Aries. That instant might fall on 4 April at 18:11 UTC one year and 4 April at 23:58 UTC the next. Cast at Paris, those two clocks produce different Ascendants and the same solar sign. A page per sun sign would hide the 15.42° and the clock, which is the entire content of the return.